Capacitive touch screens offer better light transmittance and clarity than four-wire resistive screens, and certainly not as good as surface acoustic and five-wire resistive screens.
The capacitive screen has serious reflection. Moreover, the capacitive technology of the four-layer composite touch screen is uneven in the light transmittance of each wavelength, and there is the problem of color distortion. Because the light is reflected between the layers, the image of people will be blurred.
Current: the principle of the capacitive screen is that the human body USES the electrode as the electrode element. When a conductor is close to the interlayer Ito working face and enough capacitance is added, the current flow is enough to cause the wrong action of the capacitive screen.
Although the capacitance is inversely proportional to the distance between the poles, it is proportional to the relative area and is also related to the dielectric coefficient.
Therefore, when the large-area palm or handheld conductor is close to the capacitive screen and cannot be touched, it will cause the wrong action of the capacitive screen. In humid weather, this situation is particularly serious. The fuselage of the handheld display, with the palm close to the monitor 7 cm or close to the monitor 15 cm, may cause the wrong action of the capacitive screen.
Another disadvantage of capacitive screens is that they do not react when touched or held by a gloved hand because of the added insulating medium.
Drift: the main disadvantage of capacitor screen is drift: when the environmental temperature, humidity and electric field change, it will cause the drift of capacitor screen, leading to inaccuracy.
For example, the temperature of the monitor will rise after the boot will cause drift: the user touches the screen, and the other hand near the monitor or the side of the body will drift;
Larger objects in the vicinity of the capacitive touch screen will drift, and if the user touches it and someone nearby watches, it will also cause the drift.
Capacitive screen drift is a technical flaw,
Although the ambient potential surfaces (including the user's body) are far away from the capacitive touch screen, they are much larger than the finger area, and they directly affect the measurement of the touch position.
Many others: in addition, the theory should be A linear relationship is actually nonlinear, such as different weight or wet finger levels of total power flow is different, and the change of the total current and the change of the four independent flow is nonlinear relationship, in the corners of the custom pole coordinate system is used in capacitive touch screen without origin of coordinates, drift controller cannot be detected and recovered, 4, after the completion of A/d calculation process of the x, Y coordinates of four points to the value of the touch points in the cartesian coordinate system is complicated.
Because there is no origin, the capacitive screen drift is cumulative and often needs to be calibrated on the job site.
The silicon dioxide protective glass on the outside of the capacitive touch screen has a very good scratch resistance, but it is afraid of nails or hard objects, which may damage the ITO sandwich. Whether it is injured and laminated ITO, or smearing the ITO layer on the inner surface during installation and transportation, the capacitive screen will not work properly.
